A vibration-type angular rate sensor including a primary-side control circuit that excites a vibrator in a resonance mode and a secondary-side control circuit that detects and outputs an angular velocity applied to the sensor is known in general. A vibration-type angular rate sensor like this is disclosed in Japanese Translation of PCT international Application Publication No. JP-T-2001-509588, for example.
In Japanese Translation of PCT International Application Publication No. JP-T-2001-509588, there is disclosed a vibration structure sensor (vibration-type angular rate sensor) including a first pickoff means and a drive means (first drive means) that excite a vibration structure at a resonance frequency, and a second pickoff means and a drive means (second drive means) that outputs an angular rate applied to the vibration structure. The first pickoff means and the drive means are configured to vibrate the vibration structure at a constant frequency and with constant amplitude (primary vibration). When rotation (angular velocity) is applied to the vibration structure, a secondary vibration different from the primary vibration is generated. This secondary vibration is detected by the second pickoff means, and the vibration structure is driven by the second drive means, whereby an output from the pickoff means is reduced to zero, and becomes an angular velocity output in which the magnitude of an applied drive signal is detected.
In the vibration structure sensor (vibration-type angular rate sensor), the second pickoff means of the secondary vibration is arranged at a position of 135 degrees with respect to the first drive means of the primary vibration. On the other hand, a biased error caused by an alignment error (εr), which is a misalignment (misalignment from 135 degrees) between the first drive means of the primary vibration and the second pickoff means of the secondary vibration, resulting from a mechanical error (manufacturing error) or the like in the vibration-type angular rate sensor may be caused. Thus, according to Japanese Translation of PCT International Application Publication No. JP-T-2001-509588, the biased error caused by the alignment error is canceled by adding an output signal (a signal not dependent on temperature) of the first pickoff means to an output signal of the second pickoff means or subtracting the output signal of the first pickoff means from the output signal of the second pickoff means. Specifically, the signal (not dependent on temperature) output from the first pickoff means is added to or subtracted from the output signal of the second pickoff means so that the bias error resulting from the mechanical error is reduced.